Owner's Problem Description
The owner replaced the throttle body and gasket on a 2006 Chevy SSR, restoring performance initially. However, the vehicle failed to start later on a warm day, with trouble codes P0443, P1516, and P0689 reported. The P0443 code is persistent and cannot be erased, indicating ongoing issues. The vehicle starts fine under cooler conditions, suggesting a possible thermal-related fault. The owner is seeking help without wanting to visit a dealership.
Professional Technical Analysis
The 2006 Chevy SSR, equipped with a 6.0L V8 engine and approximately 80,000 miles, presents intermittent starting issues primarily in warmer conditions following a recent throttle body replacement. Initially, the vehicle operated at full power, but the owner reported failure to start later in the day. Diagnostic trouble codes P0443 (Evaporative Emission Control System Purge Control Valve Circuit), P1516 (Throttle Actuator Control Module Throttle Actuator Position Performance), and P0689 (ECM/PCM Power Relay Sense Circuit Range/Performance) were stored in the system. The repeated presence of the P0443 code suggests a potential fault in the canister purge valve or its circuit, which directly influences the fuel vapor management system, necessary for proper fuel metering. The P1516 code indicates a performance issue with the throttle actuator, possibly linked to the recent replacement if the throttle pedal position sensor wasn't replaced concurrently. The vehicle's starting issues may be exacerbated by heat, which can affect electrical connections or components. A thorough examination of the throttle body installation, including all electrical connections and sensor functionality, is crucial. Additionally, the P0689 code may indicate issues with the power relay or power supply to the PCM, causing intermittent operational failures. Given the symptoms and codes, it is essential to utilize a professional OBD-II scanner or the GeekOBD APP to monitor live data and freeze frame information for further diagnostic clarity. Safety concerns should also be assessed, particularly related to starting issues in traffic.
Possible Causes
Most common causes (ordered by frequency):
- Evaporative Emission Control System Purge Control Valve Circuit Issue (P0443): This could be caused by a faulty canister purge valve or damaged wiring in the circuit affecting the signal to the PCM. It is common for purge valves to fail, especially around 80,000 miles, leading to improper fuel vapor management. Testing should include checking for voltage at the purge valve connector (should be around 12V) and continuity in the wiring harness. - Persistently stored P0443 code, observed issues with fuel vapor management, voltage testing indicating potential electrical failure.
- Throttle Actuator Control Module Performance Issue (P1516): This code indicates a performance issue with the throttle actuator, likely related to the recent replacement of the throttle body. If the throttle position sensor was not replaced, it may not be calibrated correctly, leading to poor communication with the PCM. The throttle actuator should respond accurately to inputs, which can be tested by monitoring the actuator position via live data. - P1516 code stored, observed irregular throttle response, potential sensor misalignment.
- PCM Power Relay or Power Supply Issue (P0689): This code suggests that there may be an issue with the power relay supplying voltage to the PCM. A faulty relay can lead to intermittent power loss, causing starting issues. Testing should include checking the relay operation, ensuring it engages, and verifying voltage supply during cranking (should be around 12V). - Stored P0689 code, intermittent starting issues, relay operation tests indicating potential failure.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Initial OBD-II Scan: Use a professional OBD-II scanner or GeekOBD APP to retrieve all stored trouble codes and freeze frame data. This information is critical to understand the vehicle's state at the time of failure. Pay special attention to the P0443, P1516, and P0689 codes, and capture any additional codes or pending codes that may provide further insight into the issue.
- STEP 2 - Live Data Monitoring: Utilize the GeekOBD APP's live data feature to monitor the throttle position sensor readings and the canister purge valve operation. Verify that the throttle position sensor is functioning correctly (should show a smooth range of values when the accelerator is pressed) and check the purge valve for proper voltage and operation during engine idle.
- STEP 3 - Electrical Inspection: Inspect the wiring and connections related to the canister purge valve and throttle position sensor. Look for signs of wear, corrosion, or loose connections that could impact performance. Use a multimeter to check for continuity and proper voltage at the connectors. Ensure a secure fit of all electrical connectors to eliminate potential intermittent failures.
- STEP 4 - Relay and Power Supply Testing: Test the PCM power relay operation by inspecting the relay and measuring the voltage output when the ignition is turned on. The relay should engage and provide around 12V to the PCM. If the voltage is low or fluctuating, consider replacing the relay. Check for any blown fuses that could disrupt power to the PCM.
